1. Field of the Invention
The subject invention is directed to fluid filtration, and more particularly, to a portable water bottle assembly having a having a replaceable filter cartridge associated therewith for filtering and dispensing drinking water.
2. Description of Related Art
Drinking water in many areas of the world contains dissolved chemicals and suspended particulate material, as a consequence of run-off and environmental contamination. Some of these chemicals and particulates have been associated with adverse physiological effects. Others have been associated with less than desirable taste and sensory perceptions.
To reduce particulate and chemical contamination, drinking water is frequently treated by chemical processes. However, these processes may introduce other types of undesirable chemical contaminants into the water. Chemicals, such as bromine and chlorine, are also frequently added to water to act as a sanitizing agent. The dangers associated with these chemicals have been questioned.
There is a general view that municipal water treatment plants often fail to adequately deal with these problems. To improve water quality, many residences and businesses now employ on-site water filters to improve water streams consumed therein.
Most systems for improving water quality use a series of filters. Filtration is the process of separating particles from a fluid suspension by use of a porous medium or by means of a medium possessing chemical properties, such as hydrophobicity, electrostatic charge, etc., which permit the medium to interact with and hold the particles to be separated from the fluid, while permitting the fluid to pass there through.
Chemical contaminants are often removed by filters through chemical absorption into, or adsorption onto, the surface of the filter medium. Optimally, it is desired that the filter medium retains most of the suspended particles and many of the chemical contaminants, but allows the fluid being filtered to pass through unimpeded. Flow across the filter medium is generally achieved by the application of a driving force, usually in the form of a pressure difference across the filter, which may be generated by external pressure applied upstream, a vacuum applied downstream, gravity, or another force.
Fluid filters are often constructed in the form of relatively rigid replaceable filter units or filter cartridges. Filter cartridges often employ granular activated carbon elements in their construct. Granular activated carbon is useful for removing organic chemicals such as chlorine, hydrogen sulfide, pesticides, herbicides, phenol, chlorophenol and hydrocarbon from water. Other filter elements may be employed in the cartridge construct to help, for example, to remove sediments such as rust and other particles. Silver is sometimes impregnated into one or more filter element to inhibit bacterial growth. Ion exchange resins may also be employed.
While filter cartridges containing granular activated carbon are known to be good at removing contaminants that affect taste, odor of the filtrate, and visible particulate matter, such filter cartridges generally are not fine enough to remove bacteria or viruses. Water may be contaminated with a number of micro-organisms including pathogenic bacteria, amoebae, flagellates, viruses and protozoa. In fact, as some water remains inside carbon granules after filtration, stagnant water in the carbon granules may act as a breeding ground for micro-organisms. Therefore, water discharged after a long period of non-use of a carbon-based filter cartridge may be contaminated with living organisms.
Recognizing that prior art filter cartridges which incorporate only a single filter medium, in particular a carbonaceous medium, suffer from the inability to remove many of the contaminants found in water, there have been developed filter assemblies employing a plurality of filter media. For example, filter assemblies have been developed that include an outer cylindrical filter structure with porosity to remove particulate matter, an inner cylindrical sorbent structure for sorbing chemical contaminants, and an inner-most cylindrical microbiological filter, preferably comprising a microporous membrane or a microporous fiber bundle for removing microorganisms. By moving water through the assembly, from the outer structure to the inner structure, particulates are removed, chemicals are adsorbed or absorbed, and microorganisms are filtered out.
There is a need in the art for a portable water bottle with a replaceable filter cartridge that is adapted to remove contaminants and particulate matter, as well as, bacteria and, optionally, viruses from drinking water. The subject invention fulfills that need.